I got to try to cut three bottles before it broke. My first worked great, the second scored a spiral so it failed, but the third warped the plastic enough that it no longer works.
Make sure that you don't try to cut on a bottle with a curved shape. My third attempt was on a bottle that got wider before it got narrow again. When I tightened it down the plastic holding the scorer warped, now the thing can't put enough pressure on a bottle to score it. I tried to fix it, but ended up just throwing it away.

Tightened the cutter down, measured the sides so they were adjusted evenly, held the bottle in place and spun the cutter. One application of boiling water and cold water. The bottle actually just fell apart perfectly

I've used a variety of things to cut and drill glass over the years, it's a fickle thing some breaks are inevitable. Making sure your line is spot on and being patient with the hot/cold water helps a lot. Also thicker glass like wine bottles take longer but tend to work better than beer bottles in my experience (though I've cut quite a few beer bottles successfully there is a higher failure rate). Very much a practice makes perf... err... better thing 😉
Cut proof gloves (or just decent leather work gloves) will prevent most injuries.

Just recently got mine. Started testing it with some boring beer bottles before trying it on a nicer bottle. The first one worked great. All the following ones I couldn't get it to make a nice circle around it. It always scored a spiral up or down the bottles, no matter how precisely I leveld it.
Any tips?

Almost certain that is a cheap knock off that won't last long. May look nice but materials used and construction are less adequate and will most likely break or wear out in a short period of time. Also the end result may not be as good as the original manufacturers product.

Thanks again for joining this drop! We have submitted the group's order with the vendor and they are working hard to prepare it for shipment.
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All of the orders have been shipped and are now on the way to you! Once tracking is available, you will receive a confirmation email with tracking information. Please allow 24-48 hours for this information to update in the courier’s system.
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Bulk order shipped! The vendor informed us that the group's order was picked up and is on its way to our warehouse in New Jersey. Based on the tracking provided, the order is scheduled to arrive on 12/27.
Expect another update from us on 12/28 or sooner if something comes up.
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Thanks again for joining this drop! We have submitted the group's order with the vendor for the Kinkajou Bottle Cutter Kit and they are working hard to prepare it for shipment.
As soon as the group's order is ready at the vendor's location, they will send the bulk shipment to our warehouse in New Jersey where our warehouse team will break it up into individual orders and ship them. The current estimated ship date from our warehouse is 12/27.
We will keep the group updated throughout the fulfillment process. You can expect an update from us by the end of the day Pacific Time on 12/15.
If you have any questions, please visit our Help Center (http://massdrop.com/helpcenter).

All of the orders have been shipped and are now on the way to you! Once tracking is available, you will receive a confirmation email with tracking information. Please allow 24-48 hours for this information to update in the courier’s system.
If you have any questions, please visit our Help Center (http://massdrop.com/helpcenter).
We're also on Instagram! We'd love to see photos of the drops you've received. Give us a follow @Massdrop and tag your pictures #massdrop. https://instagram.com/massdrop

Bulk order shipped! The vendor informed us that the group's order was picked up and is on its way to our warehouse in New Jersey. Based on the tracking provided, the order is scheduled to arrive on 11/4.
Expect another update from us on 11/7 or sooner if something comes up.
If you have any questions, please visit our Help Center (https://massdrop.com/helpcenter).

Thanks again for joining this drop! We have submitted the group's order with the vendor for the Kinkajou Bottle Cutter Kit and they are working hard to prepare it for shipment.
As soon as the group's order is ready at the vendor's location, they will send the bulk shipment to our warehouse in New Jersey where our warehouse team will break it up into individual orders and ship them. The current estimated ship date from our warehouse is 11/4.
We will keep the group updated throughout the fulfillment process. You can expect an update from us by the end of the day Pacific Time on 10/25.
If you have any questions, please visit our Help Center (http://massdrop.com/helpcenter).

I paid for this product when first offered. Have not received nor have my previous request for action been acknowledged. refuse to engage another non-accessible company to reach Massdrop. do you prefer I cancel the credit card charge?